How to distinguish between specular and retroconfigurations for Andreev reflection in graphene rings.
How to distinguish between specular and retroconfigurations for Andreev reflection in graphene rings.
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DOI：
10.1103/physrevlett.108.106603
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发表时间：
2011-10
影响因子：
8.6
通讯作者：
J. Schelter;B. Trauzettel;P. Recher
中科院分区：
文献类型：
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作者：
J. Schelter;B. Trauzettel;P. Recher
通过求解Landauer-Büttiker形式中的Bogoliubov-de Gennes方程，数值研究了石墨烯环中的Andreev反射.通过调节化学势和偏置电压，可以在电子和空穴分别源自石墨烯分散体的相同能带（逆构型）或不同能带（镜面构型）的机制之间切换。我们发现，占主导地位的贡献的Aharonov-Bohm电导振荡的亚间隙运输是在retroconfiguration和在镜面配置的周期h/2 e的周期h/e，确认从干扰散射路径的定性分析得到的预测。由于对系统的无序和适度变化的鲁棒性，这提供了一个明确的签名来区分石墨烯中的两种类型的Andreev反射过程。
We numerically investigate Andreev reflection in a graphene ring with one normal conducting and one superconducting lead by solving the Bogoliubov-de Gennes equation within the Landauer-Büttiker formalism. By tuning chemical potential and bias voltage, it is possible to switch between regimes where electron and hole originate from the same band (retroconfiguration) or from different bands (specular configuration) of the graphene dispersion, respectively. We find that the dominant contributions to the Aharonov-Bohm conductance oscillations in the subgap transport are of period h/2e in retroconfiguration and of period h/e in specular configuration, confirming the predictions obtained from a qualitative analysis of interfering scattering paths. Because of the robustness against disorder and moderate changes to the system, this provides a clear signature to distinguish both types of Andreev reflection processes in graphene.